Connection of circular knives on smooth shafts



July 15, 1969 u, u TzM 3,455,586

CONNECTION 0F CIRCULAR KNIVES ON SMOOTH SHAFTS Filed Jan. 13, 1966 I z Sheets-Sheet 1 July 15, 1969 u. KURTZMANN 3,455,586

CONNECTION OF CIRCULAR KNIVES 0N SMOOTH SHAFTIS Filed Jan. 13, 1966 2 Sheets-Sheet 2 Inventor:

United States Patent 3,455,586 CONNECTION 0F CIRCULAR KNIVES 0N SMOOTH SHAFTS Udo Kurtzmann, Huckeswagen, Germany, assignor to W. Ferd. Klingelnberg Sohne, Remscheid-Berghausen, Germany Continuation-impart of application Ser. No. 468,419, June 30, 1965. This application Jan. 13, 1966, Ser. No. 520,413 Claims priority, application Germany, July 31, 1964, K 53,629; July 17, 1965, K 56,644 Int. Cl. F1611 1/06; 136% 27/06 US. Cl. 28752 4 Claims This application is a continuation-in-part application of my copending application Ser. No. 468,419 filed June 30, 1965 and now abandoned and entitled Connection of Circular Knives on Smooth Shafts.

The present invention relates to circular knives and, more specifically, to the connection of such circular knives on smooth surface cutter shafts. The connection of circular knives or hubs for circular knives for purposes of cutting paper, cardboard, textiles, synthetic materials, sheet metal, and the like has to meet a number of requirements if such connection is to be functionally and economically acceptable.

The knives must be held concentrically, non-displaceably and non-rotatably with regard to the shaft and must be retained in their proper position because already slight deviations from the proper position may result in considerable disturbances during the cutting operation of sensitive materials, such as thin paper and textiles. In addition thereto, a connection of circular knives or hubs for circular knives on smooth surface cutter shafts must be simple so that the cutter knives can be easily mounted on and removed from the cutter shaft.

A connection of the above-mentioned type must not have any loose parts and must consist of as few parts as possible with regard to the safety of operation and a minimum of wear. A connection of the above-mentioned type must furthermore be easy to manufacture and must be so designed that the employment of wedge grooves, recesses and the like. In other words any additional machining of the smooth surface of the cutter shaft, will not be necessary. As additional requirement may be mentioned that no material axial length should be taken up by a connection of the type involved so that the distance or spacing between the knives will be a minimum.

Numerous heretofore known knife connections have tried with more or less success to meet the above-mentioned requirements. Thus, according to one heretofore made suggestion, clamping bodies in the form of rollers are employed which are arranged in the hub of the knife in one or more wedge-shaped recesses similar to a freewheel arrangement. When the hub rotates relative to the shaft, the rollers are clamped fast. The drawback of such an arrangement consists in that only a linear contact between the bodies and the shaft takes place which results in a high concentration of the clamping forces and frequently brings about an elastic deformation of the hub. Moreover, it is difficult when clamping the hub to rotate the same in such a way that an axial displacement will be safely avoided.

3,455,586 Patented July 15, 1969 ice In order to avoid the drawback of line contact, it has been suggested instead of the rollers to employ wedgeshaped clamping members which, however, have to be anchored in the cutter shaft by a key and groove arrangement. This drawback has been overcome by another design according to which a pressure member is mounted in a recess of the hub, said pressure member having an outer roof-shaped contour in conformity with the radius of the shaft. This pressure member is pressed against the cutter shaft by means of a screw or an eccentric. This last mentioned arrangement, however, has the drawback that a unilateral pressure is exerted which has the tendency to destroy the centricity of the circular knife. Moreover, connections of this type are relatively difficult to make.

According to another embodiment of a heretofore known suggested connection of circular knives to smooth surface shafts, which embodiment is intended for connecting a greater number of knives on a shaft, a pressure strip is by means of a wedge slide pressed outwardly against the bore of the knife while said wedge slide and the pressure strip are provided with a greater number of step-like wedges. This embodiment has the same drawbacks as the embodiment described in the preceding paragraph.

According to an improved likewise heretofore known connection of circular knives to smooth surface shafts, a sickle-shaped lever is provided in an annular groove of the knife for transmitting the pressing force. However, also this arrangement has the drawback that the pressure is exerted unilaterally and thereby destroys the centricity of the mounting of the knife.

According to still another heretofore known embodiment of a knife connection of the type involved, the hub body is slit open annularly over a portion of its circumference in order to form a resilient tongue, and this tongue is by means of a radially or tangentially arranged pressure screw, which is provided with a conical surface, subjected to pressure so as to press the same against the knife shaft.

According to a further heretofore known arrangement of the type involved, a concentrically effective pressure is produced by flat pressing by means of a threaded ring a flat conical resilient disc which is provided with inner radial slots. In this way the inner diameter of the resilient disc is reduced and the resilient disc is pressed on an annular extension of the knife supporting body which extension is rather thin and conveys the pressure under elastic deformation onto the shaft. Such an arrangement, however, requires a certain minimum length.

According to still another heretofore made suggestion a sickle-shaped clamping body mounted in an eccentric cutout of the hub is by means of a pinion displaced in circumferential direction, said pinion meshing with teeth of said clamping body.

Another heretofore suggested solution provides two sickle-shaped clamping bodies one of which is connected by a follow-up member with the hub, whereas the other one is connected with the shaft so that when said two parts rotate relative to each other, a clamping effect will be produced. Also this design requires too many parts and is too expensive.

There has furthermore become known a construction which for purposes of producing a clamping effect employs helical spring bands with one or more windings. These bands are anchored at one end to the nose in the supporting body Whereas at the other end there is provided a slotted clamping bolt for contacting the said spring windings so that the latter will tightly grasp around the cutter shaft and thereby effect a frictional movement of said cutter shaft.

There is also known an arrangement of the general type involved in the present case, according to which a wedge is provided in the cutter shaft and protrudes over the circumference thereof, whereas the hub has a corresponding eccentrically arranged recess. By turning the hub relative to the shaft, it is clamped fast on the shaft wedge.

Other types of connection of the general type involved employ hydraulic or pneumatic means. The hollow cutter shaft or a plurality of grooves extending in axial direction of the shaft contain inflatable hoses which are adapted to exert pressure upon pressure members or diaphragms in the shaft and bring said pressure members or diaphragms into frictional clamping connection with the cutter hub. Such an arrangement, however, requires recesses and transverse bores in the hollow cutter shaft and furthermore requires a connection with a source of compressed air.

It is, therefore, an object of the present invention to provide a connection of cutter knives or hubs for cutter knives with a smooth surface cutter shaft, which will overcome the above-mentioned drawbacks.

It is another object of this invention to provide a connection as set forth in the preceding paragraph, which is simple in construction, requires little space and is highly effective while not affecting the concentricity of the circular knife with regard to the shaft supporting same.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 illustrates partially in side view and partially in section a circular knife connection with a smooth surface shaft in conformity with the present invention.

FIG. 2 is a section along the line IIH of FIG. 1.

FIG. 2a shows a view of a split clamping ring for use in connection with the present invention.

FIG. 3 represents a modified arrangement according to the present invention on a somewhat larger scale than that of FIGS. 1 and 2, in which a pressure exerting pin is movable in radial rather than in axial direction as in the case with the arrangement of FIGS. 1 and 2.

FIG. 4 illustrates partially in side view and partially in section a modification of the invention which differs from that of FIGS. 1 to 3 primarily in that instead of pressure balls used with the embodiment of FIGS. 1 to 3, pressure rollers are employed.

FIG. 5 is a section along the line VV of FIG. 4.

FIG. 6 illustrates partially in view and partially in section a modified circular knife connection which differs from that of FIGS. 1 to 3 primarily in that two groups of different size balls are employed, FIG. 6 representing a section along the line VI-VI of FIG. 7.

FIG. 7 is a section along the line VIIVII of FIG. 6.

FIG. 8 illustrates the connections of FIGS. 6 and 7 on a larger scale than that of the latter and also indicates the direction in which the respective occurring forces act.

FIG. 9 illustrates partially in side view and partially in section still another modification according to the present invention which differs from that of FIGS. 1 to 7 in that the balls or rollers have been replaced by a plastic substance as pressure conveying means.

FIG. 10 is a section along the line X-X of FIG. 9.

The arrangement according to the present invention for connecting circular knives for cutting textiles, paper, cardboard, synthetic materials, sheet metal, and the like,

to a smooth surface cutter shaft, is characterized primarily in that a hardened thin-walled split clamping ring is reccived in an annular groove provided in the cutter and concentric therewith, said clamping ring embracing the cutter shaft with slight play, while a plurality of pressing bodies, in the form of balls or cylindrical rollers, or a plastic member, exert a concentric pressure on all sides of the outer circumference of said clamping ring. The required pressing force is produced by a screw which either directly or through the intervention of an intermediate element presses upon the pressure conveying bodies or plastic material.

Referring now to the drawing in detail and FIGS. 1 and 2 thereof in particular, the arrangement illustrated therein shows a knife body 1 with an annular groove 2 having arranged therein pressure balls 3 and a hardened thin clamping ring 4 which is split as shown at 4a in FIG. 2a. The annular groove has a semicircular cross section in conformity with the diameter of the pressure balls. The pressure force is exerted by a pressure screw 5 the front end of which is conical. This pressure screw 5 extends with its conical end between two of the pressure balls 3 and is adapted when tightened to press these pressure balls apart. The pressure is transmitted through the intervention of the balls which alternately have their outer surfaces in engagement with the groove and their inner surfaces in engagement with the clamping ring (FIG. 3). Already a relatively slight tightening of the screw will suffice in view of the multiplication of the pressure effect to bring about a safe frictional clamping of the knives to shaft 6. With this arrangement no decentralizing or tilting forces are encountered.

Merely by Way of example, the thin-walled axial clamping ring 4 may have a thickness of from 0.3 to 1 millimeter while the ball diameter in this instance may be from 3 to 10 millimeters, depending on the diameter of the shaft.

While according to the arrangement of FIGS. 1 and 2 the clamping screw 5 extends in the longitudinal direction of shaft 6, with the last mentioned embodiment it is also possible instead so to arrange the clamping screw that it extends in radial direction as shown in FIGS. 3, 4 and 5. When the arrangement is intended for heavy duty stresses, it is advantageous in conformity with FIGS. 4 and 5 to use roller bodies 7a instead of the balls 7 in FIGS. 1 to 3. Clamping screw 8 has a fiat or spherical end and directly presses through a ball 9 between two rollers. The operation of the arrangement of FIGS. 4 and 5 corresponds to that of FIGS. 1 and 2.

While the above described arrangements according to the present invention have proved highly efiicient, it has been found that at even greater efficiency with considerably higher adherence moments can be realized by a further modification of the present invention according to which the annular groove contains two groups of balls or rollers, i.e., balls or rollers of two sizes, in such an arrangement that the balls or rollers of one group or one size engage the outer diameter of the annular groove whereas the balls or rollers of the other group or size engage the clamping ring. The balls or rollers are arranged in such a way that throughout the far major portion of the length of said groove each ball or roller of one group is located between two adjacent balls or rollers of the other group. An arrangement of this type is shown in FIGS. 6 to 8.

More specifically, with reference to these figures, the knife body shown therein is of substantially the same design as that of FIGS. 1 to 3 and, consequently, the same reference numerals used in FIGS. 1 to 3 are employed in FIGS. 6 to 8 to designate corresponding parts. As will be seen from FIGS. 6 to 8, the knife body 1 is provided with an annular groove 2 which is filled with balls of two sizes, namely a group of larger balls 3 and a group of smaller balls 11. Balls 3 and 11 are arranged in said annular groove 2 in such a way that when begin ning from one side of pin 5 (which in design and purpose corresponds to pin 5 of FIG. 2) and continuing through the larger portion of groove 2 to the other side of pin 5, each smaller ball 11 will be followed by a larger ball 3. Differently expressed, it may be said that each smaller ball 11 is arranged between two larger balls 3. However, the arrangement is such that the two balls directly adjacent to and at opposite sides of clamping pin 5 are balls 3 of the larger size group. Similar to the arrangement of FIGS. 1 to 3, also according to FIGS. 6 to 8, all of the balls 3, 11 are retained in groove 2 by a thin-walled hardened split steel band or ring 4 which itself is located in the radially inner portion of groove 2 and is resilient.

The pressing bodies represented by the balls 3 and 11 are introduced into the annular groove 2 in such a way that the smaller pressure bodies 11 engage the bottom of the groove whereas the larger pressing bodies 3 engage the retaining band or ring 4. However, if desired, also the inverse arrangement is possible according to which ring 4 is engaged by the smaller pressing bodies 11, whereas the groove 2 is engaged by the larger pressing bodies 3.

It will be appreciated that when in the arrangement of FIGS. 6 to 8 clamping screw 5 is tightened, the pressure exerted by clamping screw 5 is conveyed through all of the smaller and larger pressing bodies throughout groove 2 onto split ring 4 and through the latter onto shaft 6 so that the knife body 1 will be firmly connected to shaft 6. The occurring forces are indicated in FIG. 8 by the arrows 12 and 13.

Inasmuch as the pressing forces are conveyed from pressing body to pressing body over the entire adjacent circumferential surface of shaft 1, a concentric from all sides uniformly efiective pressure will be exerted upon the knife body 1 and shaft 6 so that knife body 1 will be uniformly clamped onto shaft 1.

The adhering movement of knife body 1 on shaft 6 as produced by a relatively small clamping force to be exerted upon clamping screw 5 and conveyed through pressing bodies 3 and 11 is surprisingly high and can be influenced to a great extent by the selection of the diameter of the pressing bodies 3 and 11.

While with the arrangement of FIGS. 1 to 5, according to which all pressing bodies have substantially the same size, it may occasionally occur that two or more successive pressing bodies do not alternately engage the bottom of groove 2 and ring 4 but engage only said bottom or said ring, the arrangement of FIGS. 6 to 8 will, once the pressing bodies have been properly introduced into groove 2, always assure the desired alternate contact of successive pressing bodies with the bottom of groove 2 and the clamping ring, thereby assuring uniform clamping of knife body 1 upon shaft 6.

While according to the specific showing of FIGS. 6 to 8 the smaller size balls 11 engage the bottom of groove 2 and the larger size balls 3 engage clamping ring 4, the arrangement will operate with the same efficiency when the smaller size balls engage the clamping ring and the larger size balls engage the groove bottom.

It is also to be understood that instead of balls, also smaller and larger diameter rollers may be employed. When balls are employed, the groove bottom preferably has a semicircular cross section corresponding to the diameter of the balls engaging same. When rollers are employed, the bottom of the groove preferably has a corresponding rectangular cross section.

Finally, with regard to the embodiment of FIGS. 9 and 10, the balls and rollers of the embodiment of FIGS. 1 to 7 have been replaced by a pressure body in the form of a plastic deformable material 14 which serves as pressure conveying medium. This last mentioned arrangement has proved particularly advantageous for heavy duty operation. As plastic material in connection with this last mentioned embodiment there may be employed for instance polyvinylchloride (PVC).

What I claim is:

1. A circular cutter, which comprises in combination: an annular cutter body having an axial bore therethrough and also having a circular groove arranged in that surface of said cutter which confines said bore, said circular groove being coaxial with regard to said bore, two groups of rotatable pressure transferring means with the pressure transferring means pertaining to one group having a different diameter than the pressure transferring means of the other group, the pressure transferring means of both groups being arranged in said groove and being distributed over the entire length thereof in such a way that each pressure transferring means of one group is followed by a pressure transferring means of the other group, resilient split ring means likewise arranged in said groove and retaining said pressure transferring means in said groove, andcontrol means supported by said cutter body and operable to exert pressure upon said pressure transferring means and through the latter upon said ring means so as to exert upon the latter an at least approximately uniformly circumferentially distributed radially effective pressure to thereby reduce the inner diameter of said split ring means, said pressure transferring means being formed by two goups of balls distributed over the entire length of said circular groove, the balls of one of said groups being of a larger size than the balls of the second group, said balls of said two groups being distributed over said groove so that one ball of the smaller size group of balls is in engagement with and preceded and followed by two adjacent balls of the larger size group of balls, said control means being formed by adjustable threaded pin means threadedly engaging said cutter body and having a conical tip extending into said groove between two adjacent balls of the one size group of balls for spreading two adjacent balls in said groove away from each other to thereby place all of said balls under increased pressure in circumferential and radial direction of said groove, the balls of one of said group being in engagement with the bottom of said groove and the balls of the other group being in engagement with said split ring means.

2. A cutter according to claim 1, in which said resilient split ring means has a thickness within the range of from 0.3 to 1 millimeter.

3. A cutter according to claim 1, in which said resilient split ring means is mounted in said groove under preload while the ends of said resilient split ring means are spaced from each other by a distance at least equalling the amount by which said ends must move toward each other when forcing said resilient split ring means toward its desired minimum diameter.

4. A circular cutter, which comprises in combination: an annular cutter body having an axial bore therethrough and also having a circular groove arranged in that surface of said cutter which confines said bore, said circular groove being coaxial with regard to said bore, two groups of rotatable pressure transferring means with the pressure transferring means pertaining to one group having a different diameter than the pressure transferring means of the other group, the pressure transferring means of both groups being arranged in said groove and being distributed over the entire length thereof in such a Way that each pressure transferring means of one group is followed by a pressure transferring means of the other group, resilient split ring means likewise arranged in said groove and retaining said pressure transferring means in said groove, control means supported by said cutter body and formed by adjustable threaded pin means threadedly engaging said cutter body and extending from the outside of said cutter body inwardly in the direction toward said circular groove and operable to exert pressure upon said pressure transferring means formed by two groups of rollers distributed over the entire length of said circular groove and having a conical tip extending into said groove between two adjacent rollers of the one size group of rollers exerting upon said ring means at least approximately uniformly circumferentially distributed radially efiective pressure to thereby reduce the inner diameter of said split ring means and so as to spread two adjacent rollers of the one size group in said groove away from each other to thereby place all of said rollers under increased pressure in the circumferential and radial direction of said groove, the rollers of one of said groups being of a larger side than the rollers of the second group, said rollers of said two groups being distributed over said groove so that one roller of the smaller size group of rollers is in engagement with and preceded and followed by two adjacent rollers of the larger size group of rollers, the rollers of one of said group being in engagement with the bottom of said groove and the rollers of the other group being in engagement With said split ring means.

References Cited UNITED STATES PATENTS 2,390,168 12/ 1945 Piot 28753 2,628,111 2/1953 Smalline. 2,652,270 9/1953 Jones 287-110 X 2,089,439 8/ 1937 Silberstein. 2,872,838 2/1959 Vogel SOS-63 XR FOREIGN PATENTS 137,262 12/ 1902 Germany.

45,030 11/ 1910 Austria.

642,049 5/1962 Canada.

956,792 4/ 1964 Great Britain. 1,315,136 12/1962 France.

CARL W. TOMLIN, Primary Examiner ANDREW V. KUNDRAT, Assistant Examiner US. Cl. X.R. 

1. A CIRCULAR CUTTER, WHICH COMPRISES IN COMBINATION: AN ANNULAR CUTTER BODY HAVING AN AXIAL BORE THERETHROUGH AND ALSO HAVING A CIRCULAR GROOVE ARRANGED IN THAT SURFACE OF SAID CUTTER WHICH CONFINES SAID BORE, SAID CIRCULAR GROOVE BEING COAXIAL WITH REGARD TO SAID BORE, TWO GROUPS OF ROTATABLE PRESSURE TRANSFERRING MEANS WITH THE PRESSURE TRANSFERRING MEANS PERTAINING TO ONE GROUP HAVING A DIFFERENT DIAMETER THAN THE PRESSURE TRANSFERRING MEANS OF THE OTHER GROUP, THE PRESSURE TRANSFERRING MEANS OF BOTH GROUPS BEING ARRANGED IN SAID GROOVE AND BEING DISTRIBUTED OVER THE ENTIRE LENGTH THEREOF IN SUCH A WAY THAT EACH PRESSURE TRANSFERRING MEANS OF ONE GROUP IS FOLLOWED BY A PRESSURE TRANSFERRING MEANS OF THE OTHER GROUP, RESILIENT SPLIT RING MEANS LIKEWISE ARRANGED IN SAID GROOVE AND RETAINING SAID PRESSURE TRANSFERRING MEANS IN SAID GROOVE, AND CONTROL MEANS SUPPORTED BY SAID CUTTER BODY AND OPERABLE TO EXERT PRESSURE UPON SAID PRESSURE TRANSFERRING MEANS AND THROUGH THE LATTER UPON SAID RING MEANS SO AS TO EXERT UPON THE LATTER AN AT LEAST APPROXIMATELY UNIFORMLY CIRCUMFERENTIALLY DISTRIBUTED RADIALLY EFFECTIVE PRES- 